Transmission shift problem

since a couple of days ago, my 02 yukon has been kicking when shifting from first to second gear. Has anybody had experience with this sort of thing? aamco said theyd have to take it apart and that its be 800 plus parts to replace. mom and pop mechanic says its the throttle cable, something weird specific to yukons. please someone give me advice if you know anything. THANKS!!!

Welcome to AF. No throttle cable here, stay away from " mom and pop," this is all electronic controlled. It should be scanned for trans codes at a trans shop, careful with AAMCO, based on what they told you. The usual problem with this is either the pressure control solenoid has failed, causing the hard shifts and code 1870 or 1811, or the valve body has worn at the TCC valve bore, both of these issues are common and well known in the trans repair industry.